Well tools



March 17, 1954 L. J. HERNDON, JR. ETAL 3,125,382

WELL TOOLS Filed Oct. 20, 1960 Fig.4 M

INVENTORS Luther J. Herndon, Jr.

Jack 8. Queen 6' Fig.5 6

United States Patent 3,125,382 WELL TOOLS Luther J. Herndon, In, and Jack B. Queen, Duncan, Okla, assignors to Halliburton Company, Duncan, Okla, a corporation of Delaware Filed Oct. 20, 1960, Ser. No. 63,775 Claims. (Ci. 308-4) This invention relates to well tools and more particularly to a centralizer for centering elongate tubular members, such as well pipes, including drill pipe, casing or tubing, in other tubular members or in the bore holes of wells.

In certain well operations, such as the cementing of casing or tubing in wells, it is desirable that centralizers be easily and quickly applied to such elongate members as for the purpose of centering the well pipe, casing or tubing in the surrounding pipe or the well bore; that one size of such centralizer be usable in bore holes or well pipes of diflerent diameters; and that the centralizer accommodate itself to variations in the diameter of the bore hole or well pipe as it is moved therethrough while at all times maintaining the elongate member centered in such bore hole or well pipe.

An object of this invention is to provide a new and improved well tool for positioning an elongate member, such as Well pipe, casing or tubing, centrally in a longitudinally extending passage such as a well bore to provide a uniform annular space between the elongate member and the cylindrical surface defining the passage.

Another object is to provide a centralizer for elongate members which automatically adjusts to variations in the diameter of the passage in which the elongate member is disposed to hold the elongate member properly centered in such passage.

Still another object is to provide a centralizer having a resilient base adapted to be disposed around the elongate member and provided with a plurality of projecting ribs having recesses bifurcating at their outer ends and forming a pair of outwardly extending lobes which may flex toward and away from the base when deflected as they encounter variations in the diameter of the passage in which the elongate member is disposed.

A further object is to provide a centralizer wherein the maximum and minimum diameters of the annular areas defined by the centralizer are determined by the projecting lengths of the ribs and by the depth of the longitudinal recesses, or bifurcations in the outer portions of the ribs of the centralizer, respectively.

A still further object of the invention is to provide a centralizer of the character described formed of a resilient substance wherein the lobes of the bifurcated outer ends of the ribs are deflected apart in opposite directions laterally with respect to the inner portion of the ribs by their engagement with the Wall of the well bore hole as the device is lowered therein to prevent lateral deflection of the ribs and thus prevent misalignment of the elongate member axially in the well bore hole or passage.

Another object is to provide a plurality of centralizer sections which are easily and quickly attachable to one another to form a centralizer of any desired size.

Still another object is to provide a centralizer of simple, economical construction and which is easily secured to an elongate member which is to be centered in a passage or hole.

Additional objects and advantages of the invention will be readily apparent from the reading of the following description of a device constructed in accordance with the invention, and reference to the accompanying drawings thereof, wherein:

FIGURE 1 is a vertical partly sectional view of a tu- 2 bular member provided with a centralizer embodying the invention;

FIGURE 2 is a cross sectional view, with portions of the centralizer broken away, showing the tubular member and centralizer disposed in the passage of another tubular member;

FIGURE 3 is an end view of the centralizer prior to its attachment to a tubular member;

FIGURE 4 is an end view of a modified form of the centralizer embodying the invention;

FIGURE 5 is a front view of the centralizer illustrated in FIGURE 4; and

FIGURE 6 is a vertical sectional view taken on line 6--6 of FIGURE 5.

Referring now to FIGURES 1, 2 and 3 of the drawings, the centralizer 16 embodying the invention is shown secured to an elongate member 11, such as a well tubing, which is to be inserted into and extend into a longitudinal passage or hole, such as the bore or longitudinal passage of a well casing 13.

The centralizer It includes an elongate base 14, transversely disposed ribs integral with the base and projecting outwardly therefrom, and longitudinally extending edge flanges 16 and 17 which also extend outwardly from and along the opposite edges of the base. The base, ribs and flanges are integral with one another, the centralizer being molded in one piece of a suitable resilient substance such as rubber or a synthetic rubber.

The ribs each have beveled shoulders 18 and 19 at their opposite ends which converge outwardly to provide guide surfaces for guiding the tubular member during its movement longitudinally in the bore of the casing. The sides 20 and 21 of each rib extend divergently outwardly from the base. The ribs are bifurcated or provided with longitudinal grooves or recesses 22 in their outer surfaces to form a pair of laterally and slightly divergently outwardly extending lobes 23 on the outer portion of each rib. The ends of the ribs are spaced from the edge flanges 16 and 17, whereby a pair of clamps 25 may be engaged about the base and between each edge flange and the adjacent ends of the ribs to secure the centralizer immovably to the tubular member 11.

Each of the clamps may take the form of a flexible metal strap 26 which may be wrapped around the base and have one end inserted through a pair of parallel slits 29 and 30 formed in a flat plate 31 integral with the other end of the strap and then bent back on itself. The fiat plate has lateral tabs 32 and 33 which are bent over the bent back end of the strap to hold the strap against movement and thus securely bind or clamp the centralizer immovably to the tubular member. When the centralizer is thus secured on the tubular member, the ribs 15 are spaced from one another circumferentially around the tubular member and extend radially outwardly from and longitudinally of the outer surface of such tubular memher.

it will be apparent that any other suitable means for clamping or rigidly securing the base of the centralizer about and to the tubular member may be employed.

After the centralizer is immovably secured to the tubing 11, the tubing is lowered into the casing 13. The lower upwardly and outwardly extending or beveled lower ends 19 of the ribs engage any upwardly facing obstructions in the bore of the casing 13 to guide the centralizer and the tubing therepast, the lobes 23 of each rib 15 spreading apart or moving laterally in opposite directions relative to one another when the diameter of the casing decreases and moving laterally inwardly towards one another when the diameter of the casing increases during such downward movement through the casing. The ribs do not tend to move laterally in either diection since the two lobes of each of the ribs, which are less thick than the ribs themselves, tend to flex apart under smaller lateral forces imparted thereto than the lateral forces required to flex the inner thicker portions of the ribs nearer the base. In addition, the circumferential spacing of the lobes tends to place them under compression forces exerted inwardly at circumferentially spaced lines on opposite sides of the center of each rib which tend to equalize any lateral forces imparted to the rib. As a result, the ribs 15 do not tend to bend laterally or be displaced laterally of their longitudinally extending radial positions.

The clamp assemblies 25 are prevented from longitudinal displacement due to their placement between the ends of the outwardly projecting ribs and the edge flanges. As a result, the centralizer maintains the tubing 11 in a central or centered position in the bore of the casing 13 so that the annular space between the tubing and the casing is uniform at all points.

When it is desired to remove the tubing, the downwardly and outwardly beveled upper ends 18 of the ribs serve to guide the ribs past downwardly facing obstructions in the bore of the well casing encountered by the centralizer during such upward movement.

The centralizer may be used in well casing of different sizes whose range of radius does not exceed the depth of the grooves 22 bifurcating the outer portions of the ribs 15. For example, if the depth of the grooves, the distance between the inner surfaces of the grooves and the outermost surfaces of the lobes 23 is one inch, the centralizer when attached to a tubing 11 of a predetermined size may be used in well bores or casings of sizes which vary in radius over a range of approximately one inch. it will thus be apparent that the depth of the grooves defining the lobes 23 of each rib will control the extent to which the lobes may be spread apart and will thus determine the minimum dimension of the annular space surrounding the tubing or pipe 11 on which the centralizer is mounted.

While the centralizer 10 has been illustrated and described as being mounted rigidly on a well tubing which is then inserted into a well casing, it will be apparent that the centralizer may be mounted on a well casing or other well pipe to engage the sides of a well bore or hole as the well casing is moved downwardly into the well to center the well casing or pipe in the well bore in order that an annular space of substantially uniform dimension exists between the outer surface of the well casing and wall of the well bore so that various well operations, such as cementing, may be properly performed in the well.

It will further be seen that, While the centralizer it may be molded in desired sizes and lengths to fit various sizes of such tubular members as well tubing and well casing if desired, the centralizer It) may also be manufactured in the form of an elongate strip from which pieces of appropriate length may be cut to fit properly about the elongate member, of whatever dimension, which is to be provided with a centralizer.

It will further be seen that a centralizer has been provided having ribs formed with their outer portions bifurcated to provide laterally outwardly extending resilient lobes which are adapted to spread apart laterally with respect to the ribs on which they are formed to dset any lateral forces imposed on the ribs due to the contact of the lobes with the internal surfaces defining the passage through which the centralizer and any elongate member on which it is mounted are moved, and that the lobes thus prevent lateral flexing of the ribs which would result in misalignment or off-center disposition of the elongate member in the passage in which such member is inserted.

It will further be seen that a new and improved centralizer has been illustrated and described which is easily and quickly securable immovably about an elongate member, such as well pipe or the like, by means of clamps, and that such clamps or clamping means are held against longitudinal movement relative to the centralizer due to the provision of the end flanges outwardly of the upper and lower ends of the ribs projecting from the intermediate portion of the base of the centralizer.

In FIGURES 4, 5 and 6 is illustrated a modified form of centralizer 59 which is formed of a plurality of idential sections 53a. Each of the sections Stla includes a deformable metal plate 51 to which is bonded the base portion 52 having the outwardly projecting ribs 53. The ribs are provided at their outer ends with the longitudinal grooves 5-, which bifurcate the outer portion of the ribs to form the outwardly extending lobes 55. The base is also provided with upper and lower end flanges 56 and 57, respectively. The base 52, the ribs and the end flanges are integral with one another and are preferably molded of any desired resilient substance, such as rubber or synthetic rubber, the base 52 being bonded or adhesively secured to the deformable plate 51 in any suitable manner.

The plate 51 are provided along one side edge with inturned first hinge portions 58 and on the other side edge with complementary spaced inturned second hinge portions 59. The inturned hinge portions 59 are thus offset from the inturned hinge portions 53 so that the inturned portions 58 and 59 of adjacent centralizer sections 59a may intermesh and have the apertures formed thereby aligned to receive a connecting member or hinge pin 69. The pins 60 have external flanges or heads 61 at one end which prevent movement of the pins in one direction through the hinge portions and with a cotter key or other suitable fastening device 62 at their other end which limits movement of the pins in the opposite direction relative to the hinge portions.

It will be apparent that any desired number of the sections Elia, as required by the diameter of the elongate member to which the centnalizer is to be secured, may be connected together and then bent around such elongate member, the deformable plates 51 deforming to conform to the outer surface of such elongate member. The free ends of such assembly of centralizer sections 56a may be connected by another pin, or, if desired, any other suitable clamping or connecting means, such as the clamps 25, may be employed to secure the assembly of centralizer sections Stla to such elongate member and in this latter case the hinge portions on the free ends of the outer sections would either be severed or flattened to prevent their interference with the clamping action of such clamps.

This form of the centralizer has all the advantages of the form first described and in addition is provided with the flexible metal reinforcing plates 51 and the hinge type connecting means for connecting the sections around the well pipe or other tubular member.

The foregoing description of the invention is explanatory only, and changes in the details of the construction illustrated may be made by those skilled in the art, within the scope of the appended claims, without departing from the spirit of the invention.

What is claimed and desired to be secured by Letters Patent is:

l. A centralizer for an elongate member including: a substantially flat base disposable about an elongate member; and a plurality of longitudinal resilient ribs extending outwardly from one side of the base, each of said ribs having an outer portion provided with a longitudinal recess forming a pair of longitudinal lobes extending divergently outwardly relative to one another, said ribs extending substantially radially outwardly from the base in circumferentially spaced relation to one another when said base is disposed about said elongate member, each of said ribs having longitudinal sides which extend divergen-tly outwardly from said base and having oppositely facing end shoulders which extend convergently outwardly from said base.

2. A centralizer for an elongate member including: a base disposable about an elongate member; and a plurality of longitudinal resilient ribs extending outwardly from one side of the base, each of said ribs having a longitudinal recess providing a pair of lobes extending later- 1 ly outwardly relative to one another, said ribs extending radially outwardly from the base in cincumtferentially spaced relation to one another when said base is disposed about said elongate member, each of said ribs having longitudinal sides which extend divergently outwardly from said base and having oppositely facing end shoulders which extend convergently outwardly [from said base, the lobes of said ribs being of lesser thickness than said ribs inwardly of said recess.

3. A centralizer for an elongate member including: a base disposable about an elongate member; and a plurality of longitudinal resilient ribs extending outwardly from one side of the base, each of said ribs having a longitudinal recess providing a pair of lobes extending laterally outwardly relative to one another, said ribs extending radially outwardly vfrom the base in circumferentially spaced relation to one another when said base is disposed about said elongate member, said ribs being spaced tfirorn the ends of said base, said base being provided with end flanges extending outwardly from said one side of said base and spaced from opposite ends of said ribs.

4. A centralizer for an elongate member including: a flat base; and a plurality of longitudinally extending laterally spaced ribs extending outwardly from one side of said base, each of the ribs having a longitudinally extending recess in its outer end providing a pair of lobes extending laterally outwardly in opposite directions, each of said ribs having longitudinal sides extending divergently outwardly from said base, said ribs and said base being formed of a resilient substance whereby said lobes are flexible laterally outwardly toward said base and said base may be wrapped about an elongate member.

5. A centralizer for an elongate member including: a flat base; and a plurality of longitudinally extending laterally spaced ribs extending outwardly from one side oat said base, each of the ribs having a longitudinally extending recess in its outer end providing a pair of lobes extending later-ally outwardly in opposite directions, said ribs and said base being formed of a resilient substance whereby said lobes are flexible laterally outwardly toward said base and said base may be wrapped about an elongate member, said ribs extending outwardly from an intermediate portion of said base, said base being provided with outwardly extending flange-s spaced from opposite ends of said ribs.

6. A centralizer for an elongate member insertable in a longitudinally extending passage to hold the elongate member centered in said passage in spaced relation to the surfaces defining said passage including: a base dis posa'ble about said elongate member; a plurality of longitudinal resilient ribs extending outwardly from said base and radially of said elongate member when said base is disposed about said elongate member, each of said ribs having longitudinal sides which extend divergently outwardly from the base and having oppositely facing end shoulders which extend convergently outwardly from said base, each of said ribs having an outer longitudinal recess providing :a pair of lobes extending aterally outwardly relative to one another to engage surfaces defining said longitudinally extending passage to hold the elongate member centered in said passage.

7. A centralizer for an elongate member insertable in a longitudinally extending passage to hold the elongate member centered in said passage in spaced relation to the surface defining said passage including: a base disposable about said elongate member; a plurality of longitudinal resilient ribs extending outwardly from said base and radially of said elongate member when said base is disposed about said elongate member, each of said ribs having an outer longitudinal recess providing a pair of lobes extending laterally outwardly relative to one another to engage surfaces defining said longitudinally extending passage to hold the elongate member centered in said passage, said lobes of said ribs being of lesser thickness than said ribs inwardly of said recess, each of said ribs having longitudinal sides which extend divergently outwardly from said base.

8. A centralizer for an elongate member to be inserted in a longitudinal passage to hold the elongate member centered in said passage and uniformly spaced from the surfaces defining said passage, including: a plurality of centralizer sections, each of said sections including a plate deformable about an elongate member, a resilient base secured to a side of said plate remote from said elongate member, and a plurality of resilient ribs extending outwardly from said base; and means for securing adjacent ends of adjacent centralizer sections to one another.

9. A centralizer for an elongate member to be inserted in a longitudinal passage to hold the elongate member centered in said passage and uniformly spaced from the surfaces defining said passage, including: a plurality of centralizer sections, each of said sections including a plate deformable about an elongate member, a resilient base secured to a side of said plate remote from said elongate member, and a plurality of resilient ribs extending outwardly from said base; and means for securing adjacent ends of adjacent centralizer sections to one another, each of said ribs having a longitudinal recess providing a pair of lobes extending laterally outwardly relative to one another to engage surfaces defining said elongate passage to hold the elongate member centered in said passage.

10. A centralizer for a well pipe including: a base disposable about a well pipe and concentric with the longitudinal axis of the well pipe; and a plurality of longitudinal resilient ribs extending outwardly from one side of the base, each of said ribs having an outer portion provided with a longitudinal recess forming a pair of longitudinal lobes extending divergently outwardly relative to one another, said ribs extending substantially radially outwardly from the base and in circumferentially spaced relationship to one another when said base is disposed about a well pipe.

References Cited in the file of this patent UNITED STATES PATENTS 2,334,690 Yden Nov. 23, 1943 2,715,552 Lane Aug. 16, 1955 2,813,697 Swart Nov. 19, 1957 FOREIGN PATENTS 1,055,893 Germany Apr. 23, 1959 

3. A CENTRALIZER FOR AN ELONGATE MEMBER INCLUDING: A BASE DISPOSABLE ABOUT AN ELONGATE MEMBER; AND A PLURALITY OF LONGITUDINAL RESILIENT RIBS EXTENDING OUTWARDLY FROM ONE SIDE OF THE BASE, EACH OF SAID RIBS HAVING A LONITUDINAL RECESS PROVIDING A PAIR OF LOBES EXTENDING LATERALLY OUTWARDLY RELATIVE TO ONE ANOTHER, SAID RIBS EXTENDING RADIALLY OUTWARDLY FROM THE BASE IN CIRCUMFERENTIALLY SPACED RELATION TO ONE ANOTHER WHEN SAID BASE IS DISPOSED ABOUT SAID ELONGATE MEMBER, SAID RIBS BEING SPACED FROM THE ENDS OF SAID BASE, SAID BASE BEING PROVIDED WITH END FLANGES EXTENDING OUTWARDLY FROM SAID ONE SIDE OF SAID BASE AND SPACED FROM OPPOSITE ENDS OF SAID RIBS. 